HCV AND HIV CORE PROJECT SUMMARY Hepatitis C (HCV), HIV, and substance use disorder (SUD) are significant and overlapping public health challenges in the US. HCV and HIV are two of the most serious medical conditions affecting substance users. Injection drug use is the primary mode of HCV acquisition in the US and the prevalence of HIV among injection drug users is 100 times higher than in the general US population. Use of other substances leads to substantial additional morbidity, mortality, and costs for treating HCV and HIV patients. The high costs of new curative HCV treatments and highly effective HIV medications highlight the need to understand the economic impact of treating substance users. Novel approaches to these economic analyses are required in the new era of the Affordable Care Act, which is increasing healthcare access and promoting new integrated healthcare system organizational models. The overall aim of CHERISH (Center for Health Economics of TReatment Interventions for Substance Use Disorder, HCV, and HIV) is to develop and disseminate economic evidence that informs substance use treatment policy and HCV and HIV care of substance users, and to increase the impact of this research by addressing the needs of integrated healthcare system providers and payers. In support of this aim, the CHERISH HCV and HIV Core will have a unique combination of clinical expertise in the treatment of HCV, HIV and SUD, methodological expertise working with large administrative databases to conduct economic analyses, and experience developing and using simulation models to inform HCV and HIV policy and SUD policy. The HCV and HIV Core?s specific aims are: (1) to support the use of longitudinal data to conduct economic evaluations of treatments for HCV and HIV among substance users that address the integrated healthcare system perspective, and (2) to promote advanced simulation modeling methods that incorporate longitudinal patterns of substance use in economic evaluations of HCV, HIV and SUD treatment. We will identify data sets containing policy-relevant outcomes from a variety of settings, and initiate collaborations to conduct innovative analyses of the economic consequences of SUD, HCV, and HIV care. We will promote the use of simulation modeling so that HIV, HCV, and SUD researchers who have never before considered a simulation study can see how the data they collect from interventional trials and observational cohorts can be leveraged to make policy conclusions, and we will support these investigators to ensure that they have the tools they need to be successful. We will investigate critical simulation modeling parameters using longitudinal datasets and show how these parameters can be used in advanced simulation models to evaluate HCV, HIV, and SUD treatment. We will work closely with the Methodology Core to ensure that longitudinal data can be analyzed using advanced biostatistics, econometrics, and clinical epidemiology methods, with the Dissemination and Policy Core to plan and execute dissemination activities, and with the Pilot Grant and Training Core to evaluate and mentor pilot projects and conduct training in data analysis and modeling.